| ; |
| ; jfdctfst.asm - fast integer FDCT (non-SIMD) |
| ; |
| ; x86 SIMD extension for IJG JPEG library |
| ; Copyright (C) 1999-2006, MIYASAKA Masaru. |
| ; For conditions of distribution and use, see copyright notice in jsimdext.inc |
| ; |
| ; This file should be assembled with NASM (Netwide Assembler), |
| ; can *not* be assembled with Microsoft's MASM or any compatible |
| ; assembler (including Borland's Turbo Assembler). |
| ; NASM is available from http://nasm.sourceforge.net/ or |
| ; http://sourceforge.net/project/showfiles.php?group_id=6208 |
| ; |
| ; This file contains a fast, not so accurate integer implementation of |
| ; the forward DCT (Discrete Cosine Transform). The following code is based |
| ; directly on the IJG's original jfdctfst.c; see the jfdctfst.c for |
| ; more details. |
| ; |
| ; Last Modified : October 17, 2004 |
| ; |
| ; [TAB8] |
| |
| %include "jsimdext.inc" |
| %include "jdct.inc" |
| |
| %ifdef DCT_IFAST_SUPPORTED |
| |
| ; This module is specialized to the case DCTSIZE = 8. |
| ; |
| %if DCTSIZE != 8 |
| %error "Sorry, this code only copes with 8x8 DCTs." |
| %endif |
| |
| ; -------------------------------------------------------------------------- |
| |
| ; We can gain a little more speed, with a further compromise in accuracy, |
| ; by omitting the addition in a descaling shift. This yields an |
| ; incorrectly rounded result half the time... |
| ; |
| %macro descale 2 |
| %ifdef USE_ACCURATE_ROUNDING |
| %if (%2)<=7 |
| add %1, byte (1<<((%2)-1)) ; add reg32,imm8 |
| %else |
| add %1, (1<<((%2)-1)) ; add reg32,imm32 |
| %endif |
| %endif |
| sar %1,%2 |
| %endmacro |
| |
| ; -------------------------------------------------------------------------- |
| |
| %define CONST_BITS 8 |
| |
| %if CONST_BITS == 8 |
| F_0_382 equ 98 ; FIX(0.382683433) |
| F_0_541 equ 139 ; FIX(0.541196100) |
| F_0_707 equ 181 ; FIX(0.707106781) |
| F_1_306 equ 334 ; FIX(1.306562965) |
| %else |
| ; NASM cannot do compile-time arithmetic on floating-point constants. |
| %define DESCALE(x,n) (((x)+(1<<((n)-1)))>>(n)) |
| F_0_382 equ DESCALE( 410903207,30-CONST_BITS) ; FIX(0.382683433) |
| F_0_541 equ DESCALE( 581104887,30-CONST_BITS) ; FIX(0.541196100) |
| F_0_707 equ DESCALE( 759250124,30-CONST_BITS) ; FIX(0.707106781) |
| F_1_306 equ DESCALE(1402911301,30-CONST_BITS) ; FIX(1.306562965) |
| %endif |
| |
| ; -------------------------------------------------------------------------- |
| SECTION SEG_TEXT |
| BITS 32 |
| ; |
| ; Perform the forward DCT on one block of samples. |
| ; |
| ; GLOBAL(void) |
| ; jpeg_fdct_ifast (DCTELEM * data) |
| ; |
| |
| %define data(b) (b)+8 ; DCTELEM * data |
| |
| align 16 |
| global EXTN(jpeg_fdct_ifast) |
| |
| EXTN(jpeg_fdct_ifast): |
| push ebp |
| mov ebp,esp |
| push ebx |
| ; push ecx ; need not be preserved |
| ; push edx ; need not be preserved |
| push esi |
| push edi |
| |
| ; ---- Pass 1: process rows. |
| |
| mov ecx, DCTSIZE |
| mov edx, POINTER [data(ebp)] ; (DCTELEM *) |
| alignx 16,7 |
| .rowloop: |
| push ecx ; ctr |
| push edx ; dataptr |
| |
| movsx eax, DCTELEM [ROW(0,edx,SIZEOF_DCTELEM)] |
| movsx edi, DCTELEM [ROW(7,edx,SIZEOF_DCTELEM)] |
| lea esi,[eax+edi] ; esi=tmp0 |
| sub eax,edi ; eax=tmp7 |
| push eax |
| |
| movsx ebx, DCTELEM [ROW(1,edx,SIZEOF_DCTELEM)] |
| movsx ecx, DCTELEM [ROW(6,edx,SIZEOF_DCTELEM)] |
| lea edi,[ebx+ecx] ; edi=tmp1 |
| sub ebx,ecx ; ebx=tmp6 |
| push ebx |
| |
| movsx eax, DCTELEM [ROW(2,edx,SIZEOF_DCTELEM)] |
| movsx ecx, DCTELEM [ROW(5,edx,SIZEOF_DCTELEM)] |
| lea ebx,[eax+ecx] ; ebx=tmp2 |
| sub eax,ecx ; eax=tmp5 |
| push eax |
| |
| movsx ecx, DCTELEM [ROW(3,edx,SIZEOF_DCTELEM)] |
| movsx eax, DCTELEM [ROW(4,edx,SIZEOF_DCTELEM)] |
| lea edx,[ecx+eax] ; edx=tmp3 |
| sub ecx,eax ; ecx=tmp4 |
| push ecx |
| |
| ; -- Even part |
| |
| lea eax,[esi+edx] ; eax=tmp10 |
| lea ecx,[edi+ebx] ; ecx=tmp11 |
| sub esi,edx ; esi=tmp13 |
| sub edi,ebx ; edi=tmp12 |
| |
| mov edx, POINTER [esp+16] ; dataptr |
| |
| add edi,esi |
| imul edi,(F_0_707) ; edi=z1 |
| descale edi,CONST_BITS |
| |
| lea ebx,[eax+ecx] ; ebx=data0 |
| sub eax,ecx ; eax=data4 |
| mov DCTELEM [ROW(0,edx,SIZEOF_DCTELEM)], bx |
| mov DCTELEM [ROW(4,edx,SIZEOF_DCTELEM)], ax |
| |
| lea ecx,[esi+edi] ; ecx=data2 |
| sub esi,edi ; esi=data6 |
| mov DCTELEM [ROW(2,edx,SIZEOF_DCTELEM)], cx |
| mov DCTELEM [ROW(6,edx,SIZEOF_DCTELEM)], si |
| |
| ; -- Odd part |
| |
| pop eax ; eax=tmp4 |
| pop edx ; edx=tmp5 |
| pop ebx ; ebx=tmp6 |
| pop edi ; edi=tmp7 |
| |
| add eax,edx ; eax=tmp10 |
| add edx,ebx ; edx=tmp11 |
| add ebx,edi ; ebx=tmp12, edi=tmp7 |
| |
| imul edx,(F_0_707) ; edx=z3 |
| descale edx,CONST_BITS |
| lea esi,[edi+edx] ; esi=z11 |
| sub edi,edx ; edi=z13 |
| |
| mov ecx,eax ; ecx=tmp10 |
| sub eax,ebx |
| imul eax,(F_0_382) ; eax=z5 |
| imul ecx,(F_0_541) ; ecx=MULTIPLY(tmp10,FIX_0_541196100) |
| imul ebx,(F_1_306) ; ebx=MULTIPLY(tmp12,FIX_1_306562965) |
| descale eax,CONST_BITS |
| descale ecx,CONST_BITS |
| descale ebx,CONST_BITS |
| add ecx,eax ; ecx=z2 |
| add ebx,eax ; ebx=z4 |
| |
| pop edx ; dataptr |
| |
| lea eax,[edi+ecx] ; eax=data5 |
| sub edi,ecx ; edi=data3 |
| mov DCTELEM [ROW(5,edx,SIZEOF_DCTELEM)], ax |
| mov DCTELEM [ROW(3,edx,SIZEOF_DCTELEM)], di |
| |
| lea ecx,[esi+ebx] ; ecx=data1 |
| sub esi,ebx ; esi=data7 |
| mov DCTELEM [ROW(1,edx,SIZEOF_DCTELEM)], cx |
| mov DCTELEM [ROW(7,edx,SIZEOF_DCTELEM)], si |
| |
| pop ecx ; ctr |
| |
| add edx, byte DCTSIZE*SIZEOF_DCTELEM |
| dec ecx ; advance pointer to next row |
| jnz near .rowloop |
| |
| ; ---- Pass 2: process columns. |
| |
| mov ecx, DCTSIZE |
| mov edx, POINTER [data(ebp)] ; (DCTELEM *) |
| alignx 16,7 |
| .columnloop: |
| push ecx ; ctr |
| push edx ; dataptr |
| |
| movsx eax, DCTELEM [COL(0,edx,SIZEOF_DCTELEM)] |
| movsx edi, DCTELEM [COL(7,edx,SIZEOF_DCTELEM)] |
| lea esi,[eax+edi] ; esi=tmp0 |
| sub eax,edi ; eax=tmp7 |
| push eax |
| |
| movsx ebx, DCTELEM [COL(1,edx,SIZEOF_DCTELEM)] |
| movsx ecx, DCTELEM [COL(6,edx,SIZEOF_DCTELEM)] |
| lea edi,[ebx+ecx] ; edi=tmp1 |
| sub ebx,ecx ; ebx=tmp6 |
| push ebx |
| |
| movsx eax, DCTELEM [COL(2,edx,SIZEOF_DCTELEM)] |
| movsx ecx, DCTELEM [COL(5,edx,SIZEOF_DCTELEM)] |
| lea ebx,[eax+ecx] ; ebx=tmp2 |
| sub eax,ecx ; eax=tmp5 |
| push eax |
| |
| movsx ecx, DCTELEM [COL(3,edx,SIZEOF_DCTELEM)] |
| movsx eax, DCTELEM [COL(4,edx,SIZEOF_DCTELEM)] |
| lea edx,[ecx+eax] ; edx=tmp3 |
| sub ecx,eax ; ecx=tmp4 |
| push ecx |
| |
| ; -- Even part |
| |
| lea eax,[esi+edx] ; eax=tmp10 |
| lea ecx,[edi+ebx] ; ecx=tmp11 |
| sub esi,edx ; esi=tmp13 |
| sub edi,ebx ; edi=tmp12 |
| |
| mov edx, POINTER [esp+16] ; dataptr |
| |
| add edi,esi |
| imul edi,(F_0_707) ; edi=z1 |
| descale edi,CONST_BITS |
| |
| lea ebx,[eax+ecx] ; ebx=data0 |
| sub eax,ecx ; eax=data4 |
| mov DCTELEM [COL(0,edx,SIZEOF_DCTELEM)], bx |
| mov DCTELEM [COL(4,edx,SIZEOF_DCTELEM)], ax |
| |
| lea ecx,[esi+edi] ; ecx=data2 |
| sub esi,edi ; esi=data6 |
| mov DCTELEM [COL(2,edx,SIZEOF_DCTELEM)], cx |
| mov DCTELEM [COL(6,edx,SIZEOF_DCTELEM)], si |
| |
| ; -- Odd part |
| |
| pop eax ; eax=tmp4 |
| pop edx ; edx=tmp5 |
| pop ebx ; ebx=tmp6 |
| pop edi ; edi=tmp7 |
| |
| add eax,edx ; eax=tmp10 |
| add edx,ebx ; edx=tmp11 |
| add ebx,edi ; ebx=tmp12, edi=tmp7 |
| |
| imul edx,(F_0_707) ; edx=z3 |
| descale edx,CONST_BITS |
| lea esi,[edi+edx] ; esi=z11 |
| sub edi,edx ; edi=z13 |
| |
| mov ecx,eax ; ecx=tmp10 |
| sub eax,ebx |
| imul eax,(F_0_382) ; eax=z5 |
| imul ecx,(F_0_541) ; ecx=MULTIPLY(tmp10,FIX_0_541196100) |
| imul ebx,(F_1_306) ; ebx=MULTIPLY(tmp12,FIX_1_306562965) |
| descale eax,CONST_BITS |
| descale ecx,CONST_BITS |
| descale ebx,CONST_BITS |
| add ecx,eax ; ecx=z2 |
| add ebx,eax ; ebx=z4 |
| |
| pop edx ; dataptr |
| |
| lea eax,[edi+ecx] ; eax=data5 |
| sub edi,ecx ; edi=data3 |
| mov DCTELEM [COL(5,edx,SIZEOF_DCTELEM)], ax |
| mov DCTELEM [COL(3,edx,SIZEOF_DCTELEM)], di |
| |
| lea ecx,[esi+ebx] ; ecx=data1 |
| sub esi,ebx ; esi=data7 |
| mov DCTELEM [COL(1,edx,SIZEOF_DCTELEM)], cx |
| mov DCTELEM [COL(7,edx,SIZEOF_DCTELEM)], si |
| |
| pop ecx ; ctr |
| |
| add edx, byte SIZEOF_DCTELEM ; advance pointer to next column |
| dec ecx |
| jnz near .columnloop |
| |
| pop edi |
| pop esi |
| ; pop edx ; need not be preserved |
| ; pop ecx ; need not be preserved |
| pop ebx |
| pop ebp |
| ret |
| |
| %endif ; DCT_IFAST_SUPPORTED |
